Production requirements are such that the machines have to be able to reach very high operating speeds.
In a first machine of known type, schematically illustrated in the lay-out of FIG. 1, there is a first station S1 in which the sheets F are piled in a store M from which they are extracted one by one and placed in a straight transport line L which in reality is much longer than it appears in FIG. 1.
A second station (not illustrated) can be located downstream of the first station S1, in which a predetermined number of sheets F is stacked to form a pile.
The formation of the piles can be done in various ways, for example by successive layering operated by a battery of devices, known as “sheet feeders”; in this case, the second station can have a considerable longitudinal development which leads to a consequent increase in length of the conveyor line.
The single sheets F (or the piles) are transferred from the line L towards an envelope packaging station S2, into which the envelopes B are introduced.
The characteristics of the envelope B, in particular the location of the open side thereof, determine the orientation with which the sheet F or the pile have to reach the packaging station S2.
When the opening of the envelope B is on a short side, the sheet F is extracted from the store M parallel to the long side thereof, and in this “portrait” orientation it is transported by the line L up to the envelope packaging station S2.
This operating situation (not illustrated) is the best one for guaranteeing excellent guiding of the sheets F along the line L, also at high speed.
When the opening of the envelope B is on a long side, the sheet F has to be turned by 90° with respect to the preceding case; this orientation, known as “landscape”, is the one illustrated in FIG. 1.
It is easy to see how the stability of the sheets F, fed along the line L with this orientation, is much more precarious, even when the operating speed is not particularly rapid.
In another machine of known type, destined to fill envelopes B with the opening on the long side and schematically illustrated in the lay-out of FIG. 2, the sheets F are stacked in the store M such that the extraction is performed in the portrait direction.
With the same orientation the sheets F are in-fed and transported along the first part of the transport line L, beyond a successive station (if present) for forming a pile; in this way the greater precision in the sheet F guide can be exploited, with a greater stability of the sheets.
A terminal tract of the transport line L is arranged perpendicular to the first part and the sheets F (or piles), due to the change of direction necessary to be put into the terminal part, change their orientation to landscape so that they are correctly orientated in the envelope packaging station S2.
It is entirely evident that with this machine configuration the critical point is located in the zone in which the transport line L deviates by 90°, where the sheets, but especially the piles, risk losing the correct position, causing blockages in the machine; consequently the possibility of reaching high operating velocities is precluded.
The aim of the present invention is thus to provide a device for horizontal rotation of flat articles along a conveyor line, suitable for being associated to an automatic machine for packaging in envelopes sheets or piles, conformed in order to perform its function while maintaining the relative conveyor line with a straight development, with the aim of reaching high operating velocities.
A further aim of the invention relates to the desire to provide a device which can be activated or deactivated on command and, if inoperative, a device which is developed such as to enable in any case the transit of the articles without interference, such as to increase the versatility of the machine on which it is mounted.
A further aim of the invention consists in providing a device which is destined to perform rotations of the articles to any angle and in either direction, such as to broaden the scope of application thereof beyond the original functions.
A further aim of the invention is to provide a device of simple conception, of limited size in the development direction of the conveyor line to which it is associated, and, not least, relatively inexpensive.